What are Fiber Op,cs? Parts: • Core • Cladding • Buﬀer coa,ng types: • Single-‐mode ﬁbers • Mul,-‐mode ﬁbers
How Does an Op,cal Fiber Transmit Light? • total internal reﬂec,on • degrades • Diagram of total internal reﬂec,on in an op,cal ﬁber
A Fiber-‐Op,c Relay System • TransmiLer -‐ Produces and encodes the light signals • Op,cal ﬁber -‐ Conducts the light signals over a distance • Op,cal regenerator -‐ May be necessary to boost the light signal (for long distances) • Op,cal receiver -‐ Receives and decodes the light signals
Advantage of Fiber Op,cs • Less expensive • Thinner • Higher carrying capacity • Less signal degrada,on • Light signals • Low power • Digital signals • Non-‐ﬂammable • Lightweight
How Are Op,cal Fibers Made? 1. Making a preform glass cylinder 2. Drawing the ﬁbers from the preform 3. Tes,ng the ﬁbers
1. Making a preform glass cylinder The glass for the preform is made by a process called modiﬁed chemical vapor deposi,on (MCVD).
2. Drawing Fibers from the Preform Blank Once the preform blank has been tested, it gets loaded into a ﬁber drawing tower.
3. Tes,ng the ﬁbers • Tensile strength • Refrac,ve index proﬁle • Photo courtesy Corning • Finished spool of op,cal ﬁber • Fiber geometry • ALenua,on • Informa,on carrying capacity (bandwidth) • Chroma,c dispersion • Opera,ng temperature/humidity range • Temperature dependence of aLenua,on • Ability to conduct light underwater
Physics of Total Internal Reﬂec,on We will explain about internal reﬂec,on in an op,cal ﬁber In physics.